Article courtesy the Nortel thread....
An excerpt:
>>CIENA (Linthicum, MD - 410-694-5700), whose MultiWave Metro product fits into the metro DWDM category, is one example of a company that embodies the expansion from core to metro internally. According to Tom Mock, product marketing director for short haul and access products, evolving a technology developed in the core for use in the metro area can be a matter of simplification. “One of the major issues relates to propagation over different distances of fiber,” says Mock. “In the long distance network, you accumulate more fiber imperfections, and you have to amplify the signal periodically due to attenuation as it travels down the fiber.” Part of making DWDM cost effective for the metro means deciding which of the capabilities of a long haul system need to be kept, and which are superfluous.
Aside from expanding capacity and increasing speed, the other major area of development in metro optical networking is the evolution from a circuit-based model to more of a packet-centric architecture. As with the move toward all optical components, this migration is not absolute. Traditional, circuit-based switching and transport equipment is still dominant in nearly any deployment of metro area networks today. But service providers are by no means blind to the proliferation of IP traffic in their networks, and are looking for optical equipment better suited to the nature of Internet data than what they have today.
Vendors are translating this demand into a new class of metro products, which incorporate evolving optical transport mechanisms (like WDM) with aspects of edge data networking, like Ethernet switching and IP routing. CIENA offers an interesting vision of how metro area fiber might literally cover the spectrum of these various technologies: with hybrid switching platforms and the ability to multiplex wavelengths, each wave of light within a single piece of fiber might carry an entirely different form of traffic. The likelihood that this diversity at the edge will exist for quite some time means that metro area optical gear must, in addition to being simpler and less expensive than that in the core, be smarter and more nimble.<<
"Optical Networks: The Lambda That Roared
The real convergence revolution is about gearing up the pipelines to handle the glut. Optical networking is ready to step up to the plate with metro networks that soup-up or surpass conventional SONET. Long-haul providers are set to replace high-end switch equipment with fabrics that let photons be photons."
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